Method of and means for producing blanks for roll threaded bolts and the like



Oct. 3, 1933. w CLOUSE 1,929,184

METHOD OF AND MEANS FOR PRODUCING BLANKS FOR ROLL THREADED BOLTS AND THE LIKE Filed Feb. 10, 1952 2 Sheets-Sheet l Oct. 3, 1933. w 1 CLOUSE 1,929,184

METHOD OF AND MEANS FOR PRODUCING BLANKS FOR ROLL THREADED BOL AND THE LIKE Filed Feb. 1932 2 Sheets-Sheet 2 .0) Wlb'loowe 3 .20 in the die. The best meansheretofore employed in the Patented Oct. 3, 1933 UNITED; STATES;

ms'rnon or AND MEANS FOR rnonuomc arms FOR ROLL THREADED BOLTS AND' THE LIKE L. "Clause; 'Iimn, hio, assignor to The i National MachineryjCompa'ny, Tiflin, Ohio Application February I0, 1932. Serial No. 592,175

a'oiaims. (01. 10-24) This invention relates toa new and improved method of and means for producing blanksto be used in making roll threaded bolts and the like.

The roll threading of small size cold bolts is ini reasing in popularity as a manufacturingmethod the only difliculty being thatroll threading tends to raise the top of the thread above the diameter of the shank of the bolt, which frequently is objectionable, Several methods are employed to reduce the diameter of the shank previousto roll threading, so that the top of the thread will finally be equal in diameter to that of the shank. One method is, to reduce the diameter by the extrusionprocess, which consists in pushing the blank ,1 into the die having a shoulderand then a reduced diameter in the die block, so, that in being forced down the hole in the die the stockmust extrude or become reduced in diameter as it is passed back intothe reduced portion of the hole production of a blank having afshank with .a

portion offreduced diameter has involved the use of means forfeeding the wire stock through a shearing bushing and against a stop or gauge.

A shear knife cuts oil a suitable blank andcarries it in-iront of the stationary die inv which it is to be headed. Y The forward stroke of the heading tool first pushes the blank down the hole against a backing pin, which is adjusted for the length desired on the shank of the bolt. When a portion of the shank is to be made of smaller diameterby extrusion, for purposes of roll threading, it is now customary to use a short heading die 86 corresponding. in lengthlto that portion of the bolt shank which onewishes to use, this being of the same diameter as the wire. Back of this die there is placed another die'having a hole .of reduced diameter to take care of the extrusion, of

4? that portion of the shank whichis to. be roll threaded. In some cases the user bores back of the end of theheading die and inserts the extrusion bushing, in order to. assist in. maintaining alinement of the two dies. In any case, it'is very easy to adopt this plan. on a solid die header, However, solid die headers are only satisfactory for making bolts of short lengths. Under actual manufacturing conditions it is not practical to head in a solid diea bolt the length a Q of the shank ,-of which is more than five times its diameter, In other words, themaximumlength of a A diameter bolt that can be successfully headed ina solid die is 2 Consequently, when the manufacturer wishedto make bolts exceeding 5 this length, he has been compelled to try the use of open die headers, and then he has run into complications whichhave made it impractical to .extrude the end of the bolt shankp one reason for this is the fact that it has not been practical to split the extrusion bushing and'make it inte- 6o gral with the gripping dies because even'the finest 1 crack would cause an objectionable seam on the extruded or=reduced portion of the shank which would spoil any thread produced by rolling.

Where any effort has been made to locate the solid extrusion bushing in a backing block, it has been practically impossible to prevent one portion of the gripping die from springing back when the toggle pressure was relieved. While the toggle pressure is exerted'upon the dies and the wire 7 is being pushed back thru the dies, it is at that time that the extrusion bushing must be perfectly centered with the split gripping dies. Enormous pressures are required to hold these dies closed,

and where a number of joints'are to be found back of the dies and theusual spring iisproduced in the bed frame, there would be a tendency, when. the toggle mechanism opens, for thegripping die on one side to move slightly with the result that it would cramp the stock sufficiently "to prevent 30 the blank frombeing forced out of the extrusion die without being bent or otherwise spoiled. Consequently one of the essentials in any effort to use an extrusion die for receiving extruded metal is that'this die must be definitely held in position 35 during the gripping. portion of the cycle, but the pressure upon it must also be relieved at thetime the gripping dies are opened, in order to overcome the cramping tendency mentioned. i

' It is an object of the present'invention to pro- 9o vide an extrusion die orbushing at the rear of cooperating gripping dies for the reception of metal extruded from a blank held by the gripping dies, means being providedfor locating said bushing accurately with relation to the gripping dies, thereby to prevent the formation of an extruded portion eccentric to the body of the shank of the bolt. j

A further object is to subject both the bushing and the gripping dies simultaneously to the same high pressure gripping action and thereafter to i simultaneously relieve these parts from pressure so that there. will be no cramping of the blank between the bushing and the gripping jaws such as ordinarily results where one blank holding part is relieved of pressure independently of other blank holding portions. l

Another object is to insure accurate alineme'nt of the several blank engaging and'shaping por tions during the extrusion operation.

'With the foregoing and other objects in view which will appear as the description proceeds, the invention consistsof certain novel features of construction and combinations of parts and certain steps in the method hereinafter more fully described and pointedout in the claims.

In the accompanying drawings'the preferred form of the invention has been shown.-

In said drawings:

Figure 1 is a view partly in section of a portion of aheade'nusedin the formation of bolt blanks: having reduced. shank portions to be roll threaded.

Figure 2 is a section on line 2-2, Figure 1.

Figure 3 is a view similar to Figure li'showingia modified construction. V

Figure 4 is a section through the grlppingdies spaced apart.

Figure 5 is a section through the extrusion die or-bushing. m

Figure-6 is a plan view of a bolt blank produced by. either of the mechanisms illustrated. I In-the structure illustrated in Figure l thereis shown=a rigid structure such as -a die block 1, having a shear bushingl through which the wire stock-Sis fed intermittently inthe usual'way againstastop'or gauge B and in the path of a shear 4.-- The reciprocatingheading tool has been indicated at=5 and-isto beactuated by any suitable mechanism. 7

In the block -1 is seated a stationarygripping die 6anel a-movablegripping die 7 back of which is located a one-piece extrusion die or bushing 8 the-bore or cavity 9 in which iscoaxial with the cavity lo-between the dies-fi-and 7 when they are closed together.

Agripping slide 11 is mounted in block 1 and carries die '7. slide is adapted to be operated in-properly timed relation with the tool 5'by any suitable mechanism, such as the toggle set 12. 7

. force the blank backinto the cavity 10 which is approximately of the same diameter as the stock. During the shaping action-of tool 5 the jaws 6 and 'Iwill be heldtogether tightly by the toggle action and at the .sametime the bushing 8w11l be subjected to-the same pressureso that .all of.

the dies 6, 7, and 8'will'be thrust laterally in the samev direction under the same presure; thereby equally compensating for any compression of materials and'resiliency oftlie'bed'frame; Consequently the bores 01' cavities 9 andll) will be held correctly alined as the stock ispre'ssed back into the dies". V

.Whether themachin'e'beof theone stroke, or of the'two-stroke design, a portion of the-metal of the stock will be'extruded back into the cavity orbo're 10 which'is'of' less diameter than the stock, and that portion of theblank'le'ft' outside of the dies will be shaped intothe head of the" bolt or other article" being shapedi I Immediately following the formation of the blank and during the'b'ackward movement of the tool 5; the togjgle set" 12 acts to relieve pressure on the dies, m'o'ving'the 'die'7the'veryslight disin plan and partly tance from the die 6 necessary to eliminate the gripping action. As soon as pressure is thus released the die 6 has a tendency to shift slightly in the same direction as die 7, this being due either or both to resiliency in the bed frame and the block' liarid to'the resiliency in the die.

Should the reardie or bushing 8 be held immovably back of the gripping dies, the slight relative movement of die 6 would tend to cramp or bind upon the shaped blank with the result that the blank could'not be'kicked out or ejected without injury thereto. In the present case, however,

1'7, .as shown in Figures 3and4. This counter bore is adapted to receive oneend of the die or bushing .18. formed, in one piece'and havinga counterbore 19 .at the front end. offits cavityorbore20. The diameter of this counterborecoim cides with that of the bore or cavity .17.

v The operation of the modified structure is the same as that previously described and positively prevents a binding action on or distortion of the blank. I

The blank produced in both forms of machine has been shown in Figure 6 and includes the head21, shank body 22and reduced shank portion 23. This latter portion is adapted to be threaded by the roll pjrocess,-the metal displaced by the threading operation be ng forced outwardly so that the edges. of the threads ,will' befiush with the surface of 'the portion 22.

It is to be understood, of course, that bolts and other articles of different shapes, styles .and sizes to be threaded by the roll [method can be produced. by the mechanism herein described and as separate gripping dies are employed, the art cle produced can be of any length desired.

What isclaimed is:

1; A paratus for producing ametal article hav ing a shank with a portion reduced in'dianieter,

includ ng a rigid structure, a stationary die, an

extrusion die or bushing at'one end thereof; said dies bearing laterally against the structure, a movable gripping die; and means forexerting equal pressures against the gripping dies and the extrusion die to closethe gripping dies and bind the stationary die and the extrusion die against said structure, and for simultaneously relieving the dies of'pressure, said dies providing coaxial cavities for the reception of'stock, the cavity in the'extrusion die being of less diameter than the cavity formed by the gripping dies.

2. Apparatus for producinga metalarticle having a shank with a portion reduced in diameter, including a one-piece extrusion die orbushing, stationary and movable gripping dies at one end thereof, there being coaxial, communicating stock receiving cavities in the dies, the cavity in the extrusion die being of less diameter than the cavity of the gripping dies, and means operating intermittently for simultaneously subjecting all of the dies to equal transverse pressure and for simultaneously relieving all-of'thedies from pressure.

3. Apparatus for producing a metal article having a shank with a portion reduced in diameter, including a rigid structure, an extrusion die or its the bore of the gripping dies, means for forcing stock longitudinally into the bores, and means for exerting equal transverse pressure upon all of the dies during said forcing operation to close the gripping dies together and to bind the extrusion die and the stationary die against said rigid structure, said means being shiftable after said forcing operation thereby to simultaneously relieve all of the dies from external pressure.

4. A means for shaping a blank and for releasing it without transverse binding thereon or distortion thereof, including relatively movable gripping dies having a stockreceiving bore or cavity, an extrusion die at one end thereof having a bore of less diameter than that in the gripping dies, a rigid lateral backing for the extrusion die and one of the gripping dies, means for subjecting all of the dies to transverse pressure equally and simultaneously to bind the extrusion die and one of the gripping dies against said lateral backing and for simultaneously relieving the dies from transverse pressure, thereby to' mainis being shaped therein underpressure and after tain the bores in axial alinement both while stock simultaneously relieving all of the dies from all external pressures, thereby to maintain the bores in the dies in axial relation during the formation of a blank, and relieving the formed blank from unequal lateral pressures by the released dies.

v8. In a metal forming machine, gripping dies, a one-piece extrusion die at one end thereof,

means for closing the gripping dies. and subjecting all of the dies simultaneously to equal lateral pressure, a rigid means for resisting equally the pressures exerted through all of the dies, thereby.

to maintain the :dies in correct working relation atall times while under pressure, said pressure exerting means being shiftable to relieve all of the dies from lateral pressure simultaneously thereby to maintain their correct axial relation after the forming operation and prevent unequal lateral pressures by therelieved dies upon the work;

7. In a metal forming machine, gripping dies,

a one-piece extrusion die at one end thereof, means for closing the gripping dies and subjecting allof the dies simultaneously to equal lateral pressure, a rigid means for resisting equally the pressures exerted through all of the dies, thereby to maintain the dies in correct working relation at all times while under pressure, said pressure cluding an extrusion die, a die at one end thereof, said dies having communicating work shaping cavities in a predetermined relation, and means for subjecting the dies simultaneously to equal transverse pressures during the shaping operation and for simultaneously relieving said dies and the work therein from all transverse pressure, thereby to maintain accurately at all times 7 the predetermined relation of the cavities.

9.. The method of producing a metal shank having an extruded portion which consists in subjecting a shaping die and an extrusion die at one end thereof simultaneously to equal transverse pressures and thereafter simultaneously re- WILLIAM L. .CLOUSE. 

